No serious entrepreneur will start a new business without delving into a carefully prepared business plan. This approach should be applied by the owners of country houses when they make decisions on construction, laying communications, on the introduction of one or another life support system in their possessions. One of the most important problems of such a plan is the need to create an efficient and, if possible, minimally costly system for autonomous heating of the building.

Gas heating is by far the most attractive. But if the house is not connected to the gas pipeline network, and in the foreseeable future there are no “progress” in this area, then its owners will have to make an important decision in favor of some other source of energy. Option - use of imported liquefied gas, for which it will be necessary to organize a capacious underground storage - a gas tank.

But Is it profitable to heat a house with liquefied gas? from a gas tank? IN how much will it cost to heat a house within one season? Our post will help you figure this out. Or rather, even - not to figure it out, but to calculate the costs for the future using an online calculator.

How to determine the consumption of liquefied gas?

If you think about it, there is no particular difficulty here. The calorific value (calorific value) of the reduced gas (LNG) of the most common type (propane-butane mixture G30) is known. It is 42.5 MJ/kg. That is, burning a kilogram of LNG releases 42.5 megajoules of heat.

At the household level, we are probably more accustomed to measuring energy in other units, in watts and kilowatts. And it is more convenient to perceive a liquid substance in terms of volume, for example, in liters. It is not difficult to recalculate, knowing the density of LNG and the relationship of fundamental physical quantities - the energy potential of liquefied gas G30 is approximately 6.58 kW / dm³, in other words - per liter.

And how to find out the need of a particular house for thermal energy, so that in winter it maintains a comfortable temperature for all residents? Nothing is impossible either!

The required amount of heat is easy to calculate!

The simplest approach is to take 100 watts for each "square" of area. But this is a very generalizing ratio, which can give considerable errors both in one direction and in the other. It is better to use another algorithm, also supported by a convenient online calculator. You will find this in the publication of our portal.

When calculating gas consumption, the efficiency of the boiler and some other nuances are also taken into account.

The whole calculation is embodied in the calculator below. If there are ambiguities, explanations to the program will help.

Autonomous gasification has two significant columns in the estimate: installation of a gas tank and annual fuel consumption. We will tell you how much you will spend on liquefied petroleum gas (LPG) when living on an area from 50 to 800 m 2.

The whole article in 1 table

Popular house areas	Gas consumption per month	Gas consumption during the heating season (7 months)	Gas consumption per year

LPG at a price of 17.80 rubles/l as of 01/29/2019.

Gas consumption calculator for home heating

We made a calculator based on heat loss at home. The room warms up competently if the heating compensates for the thermal energy that the building loses through the roof, doors, walls, windows per unit of time.

The calculations include the height of the ceilings, the presence of an attic or basement, building material with different heat losses:

foam blocks - 32.7 kW / m 2;

brick - 27.6 kW / m 2;

tree - 26.1 kW / m 2.

Calculate online

House area (m2)

Ceiling height (m)

Attic

No Yes

None Heated Unheated

house material

Foam blocks Brick Wood

How exactly is the calculation

The final indicator of LPG consumption per year is derived using several formulas:

We calculate the gas consumption without hot water supply (kW / h): house area × ceiling height × material heat loss × attic and basement coefficient.

We find the gas consumption with DHW (kW / h): consumption without DHW × coefficient for DHW.

We translate the kW / h indicator into Kcal / h, then into m 3 / h, then into l / h.

Calculate the annual consumption: l/h × operating hours of the boiler per year.

In the process of calculations, we take into account a number of indicators:

The coefficient for accounting for hot water supply is 1.15.

The coefficient of the attic and the heated basement is 0.95.

The coefficient of the attic and unheated basement is 1.

Coefficient without attic + heated basement - 1.

Coefficient without attic + unheated basement - 1.05.

The coefficient without an attic and without a basement is 1.1.

The coefficient for converting energy (kW) to calories (Kcal) is 1.163.

The conversion factor from m 3 to liters of LPG is 2.37.

Boiler operating hours per year - 2,265.

Boiler efficiency - 0.92.

Unaccounted for gas consumption variables in a private house

The calculator still gives the average result. Much more data is needed to make accurate predictions:

Desired room temperature.

The average temperature of the coldest week of the year.

Number of windows, their height and width.

Window to floor area ratio: 10-50%.

Type of windows: conventional with double glazing, double glazing, double glazing.

Number of floors, upper and lower floors.

Characteristics of the outer walls:

masonry in 1-3 bricks 25-76 cm thick;

log house made of logs with a diameter of 20-25 cm;

log house from a bar 10-20 cm thick;

frame wall 20 cm thick (board, mineral wool, board);

foam concrete 20-30 cm thick.

Important adjustments are made by in-house gas equipment:

the number of burners on the stove;

the presence of an oven;

real (not passport!) gas boiler power;

device type: standard or condensing boiler.

The condensing boiler uses the potential of water vapor from the products of gas combustion. The equipment uses the received heat as efficiently as possible and reduces fuel consumption by 15%.

If you want to determine the gas consumption for your home, taking into account all the data, contact an engineer.

The gas tank is selected according to the number of fillings. The optimal indicator is 1-2 times a year. The minimum tank should be enough for 7-8 months - the heating season.

Consumption of liquefied gas per season

According to SP 131.13330.2012 Building climatology (updated edition of SNiP 23-01-99), the heating season in Russia is 207 days. It's about 7 months.

Also important information: the boiler does not work around the clock. On average, heating operates 10 hours a day.

We carried out calculations based on the initial data:

brick house without attic and basement;

floor height 3.2 m;

The efficiency of the gas boiler is 92%.

Indicators for the frequency of refueling are averaged. We have set the same fuel costs for each month. In reality, accommodation can be seasonal or short-term, consumption differs depending on the season.

The ratio of the area of ​​\u200b\u200bthe house and the volume of the gas tank (GG)

GG volume (m 3 )	Full gas station GG (l)	How much gas is enough (month)
		50-100 m2	150 m2	200 m2	250 m2	300 m2	350-450 m2	500-600 m2	800 m2
		3 802 l/year	5 703 l/year	7 603 l/year	9 504 l/year	11 405 l/year	17 107 l/year	22 809 l/year	30 412 l/year
2.5	2 125	6.7	4.5		2.7		1.5	1.1	0.8
2.7	2 295			3.6		2.4	1.6	1.2	0.9
4.6	3 910						2.7		1.5
4.8	4 080	12.8	8.5	6.4	5.1	4.2	2.8	2.1	1.6
4.85	4 112		8.6	6.5	5.2	4.3	2.9	2.2	1.6
	4 250	13.4			5.4	4.5		2.2	1.7
6.4	5 440		11.4	8.5	6.8	5.7	3.8	2.8	2.1
6.5	5 525	17.4	11.6	8.7	6.9	5.8	3.9	2.9	2.2
6.6	5 610	17.6							2.2
8.6	7 310			11.5		7.7		3.8	2.9
9.1	7 735	24.4			9.7		5.4
9.15	7 777	24.5	16.4	12.3	9.8	8.2	5.5	4.1	3.1
9.6	8 160	25.7				8.6	5.7	4.3	3.2
	8 500			13.4	10.7	9 Capacity reserve too large or too small
optimal
perfect	Best to install for the heating season
with a margin	A single charge is enough for a year

Houses with an area of ​​800-1000 m2 are serviced by:

gas tanks of industrial volumes of more than 10 m 3 (installation is more difficult);

two containers located side by side (8.6, 9.1 or 9.15 m 3).

Liquefied gas consumption per month and year

Let's go through the costs of refueling a gas tank for houses of different sizes. We use the current LPG price at the beginning of 2019 - 17.80 rubles / l. This is the cost of refueling in our company.

House area (m 2)	Gas consumption per month (l)	Gas price per month (rub.)	Gas consumption per year (l)	Gas price per year (rub.)

Thus:

gas consumption for heating a house of 100 m 2 - 68 thousand rubles a year;

gas consumption for heating a house of 150 m 2 - 101 thousand rubles a year;

gas consumption for heating a house of 200 m 2 - 136 thousand rubles a year.

We have selected examples of using autonomous heating on the ForumHouse forum. Owner experiences vary. In the project, the insulation of the house, the climate, the needs of the residents and the quality of the boiler are important.

Case 1 The user actively spends LPG - permanent residence with regular showers. A 2,300 l refill lasts almost 2 years at a room temperature of at least 21°C. Expenses are reduced by using the fireplace 6 times a month - 3 hours of burning and 9 hours of smoldering.

Yearly expense: 20,700 rubles (1150 liters at 18 rubles/l). House 125 m2.

Case 2 The user insulated the house well and installed a low-temperature boiler. In winter, did not take hot water. The daytime temperature in the rooms is 23°C, the night temperature is 20°C. Daily gas consumption from 6 to 12 liters.

Yearly expense: 15,000 rubles (1000 liters at 15 rubles/l). House 120 m2.

Case 3 The user heats the house and the garage. There are problems in insulation: heat loss through the door, floor and ceiling. Gas consumption is about 15 liters per day. The day temperature in the rooms is 22°C, the night temperature is 19°C.

Yearly expense: 81,000 rubles (5,475 liters at 15 rubles per liter). House and garage 165 m 2 .

Case 4 The user lives at the dacha on weekends. Heats only the first floor of the two. On weekdays, in the absence of residents, the temperature is automatically maintained at 7 ° C. DHW has not been started yet. Applies remote control of heating through a ZONT room thermostat with its own SIM card.

Yearly expense: 33,900 rubles (2,275 liters for 14.90 rubles/l). House 190 m2.

History instead of conclusions

The user with the nickname Blondinka 99 permanently lives in a frame house with an area of ​​100 m2. The temperature in the rooms is maintained at 25°C.

One refueling of the 4,800 l gas tank was enough for 3 years of use! The expense was 20 thousand per year.

Heating on liquefied gas is more expensive than connecting a home to a main pipeline. However, "blue fuel" has been and remains the cheapest source of energy for heating systems in residential and industrial buildings. Moreover, the expediency of using its liquefied or natural version can be determined only after calculating the gas consumption for heating the house. This is what we will do.

How to calculate the need for thermal energy

The simplified formula for such a calculation looks very simple - 1 kW of thermal energy is spent on heating 10 m 2 of the building area. A more accurate formula operates not with areas, but with the cubic capacity of the house, taking into account also the height of the ceilings in the room. But for dwellings of a standard type with a ceiling height of 2.5-2.7 meters, the above simplified proportion is valid. An accurate calculation of the need for thermal energy operates not only with the volume of heated space, but also with the heat resistance of walls, openings and ceilings. In addition, in this case, the average annual temperature and other nuances are taken into account.

However, in order to calculate the volume of fuel, a simple formula will be enough for us: 1 kilowatt = 10 square meters. As a result, it is necessary to spend 15 or 20 kW, respectively, to heat a building with an area of ​​150 or 200 "squares". And that's just an hour. But the boiler does not consume gas every minute. The period of work / idle time is divided here in the proportion of 50/50 percent. Therefore, a house of 150 square meters will spend 180 kW (15x24 / 2) per day, and a dwelling with an area of ​​two hundred square meters - 240 kW.

The cold season in our latitudes lasts from October to April - 7 months or 210 days. Therefore, the annual consumption of thermal energy will be 37,800 and 50,400 kW. We will focus on these values ​​in our further calculations.

How much heat is given off by liquefied or natural gas

We already know the annual consumption of the heating system. Now we must calculate the calorific value of the energy source itself - liquefied and natural gas. Using these values, we will be able to reach the amount of substance burned in the furnace of a gas boiler per year.

Calorific value is the ratio of the amount of kilowatts of energy released during the oxidation of fuel to a unit of mass or volume. Since we are interested in the main (natural) or liquefied gas used for heating a house as an energy source, then, as a measure of a substance, we will operate in cubic meters or liters. According to tabular data, the calorific value of natural gas is 33.5 MJ / m 3 or 9.3 kW / m 3 (a coefficient of 1 kW = 3.6 MJ is used for conversion). That is, when a cube of gas is burned, 9.3 kW of thermal energy is released.

LPG is a mixture of propane, ethylene and other combustible carbohydrates. And it is more "caloric" than dietary natural fuel. According to tabular data, the calorific value of a kilogram of such a substance is 45.20 MJ or 12.5 kW. But the generally accepted "unit" of liquefied fuel is liters, and its density is 0.524 kg / l. Therefore, we can say that during the combustion of a liter of liquefied mixture, 6.55 kW of thermal energy is released.

Calculation of the amount of fuel for heating a house

So, above in the text, we found that 9.3 or 6.55 kW of thermal energy are released from a cubic meter or liter of natural or liquefied gas, respectively. And this means that to generate 37,800 and 50,400 kW (costs for the cold season for houses of 150 and 200 squares), we need:

• 4064 and 5419 cubic meters of natural gas (37800/9.3 and so on).
• 5771 and 7695 liters of liquefied fuel (37800 / 6.55 and so on).

For accuracy, we must add 10% to these values, since the efficiency of a gas boiler is 90 percent (a tenth of the gas combustion energy is wasted). As a result, we see the following picture:

• Estimated gas consumption for heating a house with an area of ​​150 m 2 - 4471 m 3 or 6348 liters.
• The approximate fuel consumption for heating a building for two hundred squares is 5960 m 3 or 8464 liters.

The specified gas consumption is calculated for the entire cold season - seven months, from the beginning of October to the end of April. Therefore, in a warm year, you are likely to spend less gas than we calculated. However, even these results allow us to determine what is more profitable - natural or liquefied fuel.

Which gas to choose - which is more profitable?

To connect to the main gas pipeline, the user will have to pay for the project and installation work. And these expenses cannot be called insignificant. Growing appetites of gas services make gasification of dwellings a very costly undertaking. However, all these expenses pay off during operation. As of March 2017, the cost of a cubic meter of gas, depending on the region of the Russian Federation, ranges from 4.44 to 8.66 rubles. The average price is 6.55 rubles. As a result, natural gas heating of a house of 150 or two hundred square meters, taking into account the estimated consumption rate for the season, will cost 29,825 and 39,038 rubles.

Liquefied fuel does not require a tie-in to the main, but for its storage it is necessary to build a gas tank - a container that receives the required amount of fuel. In addition, this container will have to be periodically filled with gas, which is delivered to the site using special vehicles, and this service is not cheap. And the gas tank will have to be repaired and maintained. After all, the safety of all residents of a house heated by liquefied gas depends on its condition.

At the beginning of spring 2017, a liter of liquefied gas at gas stations cost from 11 to 20 rubles, depending on the region of the Russian Federation. The average cost of this fuel was 15.5 rubles. Therefore, heating a house with liquefied gas for 150 square meters will cost 98,394 rubles. For housing with an area of ​​two hundred square meters, you will have to pay even more - 131,192 rubles. As you can see, liquefied fuel has overtaken natural gas by 3.3 times. Therefore, the conclusions about profitable / unprofitable suggest themselves - natural (main) gas, with all the bureaucracy and complexity of the connection process, will be much more profitable than liquefied fuel.

How to reduce fuel consumption for a private house owner

The amounts mentioned above can stun an impressionable tenant or an ordinary citizen. Well, what can you do - "your home" was an expensive pleasure at all times. However, unlike a city dweller living in an apartment, the owner of private housing can change heating costs in his favor.

To do this, he will need to do the following:

• To insulate the facade, foundation, roof, attic and basement ceilings - even a thin layer of thermally insulating material can win back at least a couple of thousand, or even a whole dozen, from the gas bill.
• Replacing old windows with modern double-glazed windows, putting a heat-resistant canvas in the doorway - this is another 5-10 thousand minus. Moreover, it is worth taking up doors and windows in the first place, since they generate at least 40 percent of heat losses.
• Put a heat accumulator in the basement or boiler room, change the wiring diagram to a double-circuit or collector version, which provides the possibility of spot thermoregulation of radiators, purchase a boiler with high efficiency. Now on sale there are excellent 95 percent devices. In this case, savings can be up to 10-15 percent of the total bill.

In a word, it is necessary, firstly, to increase the heat resistance of the house, and secondly, to use more energy-efficient equipment. And no one is forcing you to make these changes in one season. You can start with windows, then upgrade the cauldron and get close to walls and ceilings. As a result, you can save up to a quarter of the announced costs.

The nominal gas consumption for heating a house is 100 m², for a month or for the entire heating period, if the system has already been installed and has been in operation for a long time, it is quite simple to calculate - it will be enough to take meter readings at the beginning and at the end of the month during the year, sum them up, and then calculate arithmetic mean parameter. Another thing is if you need to know this data at the stage of drawing up a house project in order to make a choice of an economical and efficient energy source and appropriate heating equipment.

Therefore, the question of how to correctly determine the weighted average gas consumption for heating a building of a given area is so important. There are several options for such calculations.

The procedure for carrying out calculations for heating with network gas supply

Natural gas supplied to consumers through engineering networks is by far the most optimal energy carrier for organizing a heating system for private housing. This is due to the low price of fuel, the absence of the need to create its reserves, and the rather high efficiency of modern gas equipment.

Naturally, when choosing a gas boiler for heating a house, it is necessary to focus on its power, since not only the efficiency of the entire heating system, but also the energy consumption will depend on it. However, gas consumption is affected not only, and not so much by the power of the boiler, but by many other factors that should also be taken into account. These include the climatic conditions of the region of residence, the design features of the building itself, the area and height of the ceilings of heated rooms, the quality of insulation of building structures, the number and type of windows, and other important parameters.

It should be understood that the nameplate power of the boiler shows its maximum capabilities, which, of course, must be higher than the required characteristics. So, for example, after making calculations in the required heat output for heating a house, the optimal model of the heater is always selected with higher rates. For example, if as a result of calculations it is obtained that the heating system requires 12–13 kW, then the owner will most likely select a boiler with a power of about 15–16 kW.

All this is being said now in order to clarify: it would be erroneous in the preliminary calculation of gas consumption for heating and planned costs to rely only on the characteristics indicated in the technical documentation of the boiler. The list of product parameters usually contains gas consumption (m³ / h), but this, again, is to achieve the power declared by the manufacturer. If we take these indicators as a basis, then the total results may seem daunting!

But it is necessary to correctly calculate at least an approximate gas consumption not only in order to make sure that it is the most economical fuel, but also to determine what measures can be taken to reduce consumption, and hence reduce regular payments for it.

The main indicator from which you need to start calculations is, rather, not the declared power of the heating device, which is still unlikely to be used "to its fullest", but the necessary thermal power for high-quality heating of the house and replenishing its heat losses.

Very often, the ratio of 1 kW of thermal energy per 10 m² of heated space is taken as the basis for such heat engineering calculations. This approach, of course, is very convenient for calculations, but still does not fully reflect the real conditions of a particular house and region of residence.

It is better to make a more thorough calculation, taking into account the main factors affecting the required thermal power. It is quite easy to do this if you use the method proposed on our portal.

How to independently calculate the required thermal power?

An accessible methodology for conducting independent calculations is given in the publication of the portal dedicated to.

The value obtained as a result of the calculations will become the “starting point” for determining the average gas consumption for heating.

Further calculations will require a formula that takes into account the energy potential embedded in the "blue fuel", that is, the amount of heat that is released during the combustion of one cubic meter of gas.

V = Q / (Ni × ηi)

Let's decipher the notation:

• V- the desired value, that is, the gas flow to obtain a certain amount of thermal energy, m³ / h.
• Q- the required thermal power, W / h, to ensure comfortable conditions in the premises.

How to calculate it - already decided. But again, an important remark needs to be made. As can be seen from the calculation conditions, the obtained value will be the maximum calculated for the most unfavorable conditions of the coldest decade of the year. In reality, there will not be so many such periods during the entire heating season, and even the boiler, with a well-planned heating system, never works constantly. And since our goal is to determine exactly the average, and not the peak gas consumption, it will not be a big mistake to take the average value of the generated power as 50% of the calculated one. Again, not to be confused with the nameplate capacity of the heating boiler.

• Hi- specific lower calorific value of gas combustion. This is a calculated tabular value that complies with existing standards. So, for network gas, it is taken equal to:

Pay attention to the type of gas. Most often, G20 is used in household networks. But the gas of the same second group can also be used, but already of the G25 type, which is characterized by a high nitrogen content. Naturally, its energy potential is less. If you do not know what type is used in your network, it is easy to check with the regional gas supply organization.

You might be interested in information on how to choose a quality

One more nuance. There is one more value in the table - hs. This is the so-called higher value of the calorific value of gas. The point is that the water vapor formed during the combustion of gas also has latent thermal energy, and if it is used, then the overall return on fuel naturally increases. It is this principle that is applied in a new generation of boilers - condensing, in which, due to the transfer of steam to a liquid state of aggregation, another 10% of heat is taken. That is, the indicated indicator can be taken as a basis for calculations for heating systems with boilers of this type.

The specific heat of combustion is indicated in joules, but for the correct calculation it must be converted to watts. The ratio is as follows:

1 kW = 3.6 MJ

In our case it turns out:

• ηi- the efficiency of the boiler, that is, a value showing how efficiently in a particular model the thermal energy obtained from gas combustion is spent precisely on heating the coolant.

This is the passport value of the product. In modern models of boilers, it can also be indicated by two values ​​\u200b\u200b- according to the highest and lowest calorific value of gas, through a fraction sign: Hs / Hi, for example, 92.3 / 84%. Naturally, you can choose a value corresponding to the actual operating modes of the boiler. But, as a rule, for a reliable calculation, “without embellishing” the capabilities of the equipment, the value for the Hi mode should be taken.

So, all the data for the calculation are known - and you can proceed to practical calculations. Let's look at an example:

Suppose it was calculated that 9.4 kW of thermal energy is needed to effectively heat a particular house of 100 m². Network gas - G20. Boiler efficiency - 0.88. It is required to determine the average gas consumption for heating.

As already mentioned, to determine the average flow rate, the required thermal power can be divided by two, that is, we take for calculations 9.4 / 2 = 4.7 kW

V = 4.7 / (9.45 × 0.88) = 0.565 m³/h

• For a day, on average, it is spent - 0.565 × 24 = 13.56 m³;
• Monthly average - 13.56 × 30.5 = 413.71 m³;
• The heating period in different regions may differ in its duration. But, for example, take 7 months:

413.71 × 7 = 2896 m³

Knowing the price of one cubic meter of gas, you can roughly plan your "accounting" for the upcoming heating season.

Once again, it should be emphasized that the resulting value of consumption per hour is a very average. Of course, at the peak of winter frosts it will be higher, but then it will “recoup” in the autumn or spring months, during thaws or during periods of stable weather normal for the region.

To simplify the task for the reader, we will place a calculator that will help determine the average hourly, daily and monthly consumption of natural gas. The total costs will then be easy to calculate, given the approximate duration of the heating season in the region and the level of prices for "blue fuel".

When arranging the heating system and choosing an energy carrier, it is important to find out the future gas consumption for heating a house of 150 m2 or another area. Indeed, in recent years, a clear upward trend in natural gas prices has been established, the last rise in price by about 8.5% occurred recently, on July 1, 2016. This led to a direct increase in heating costs in apartments and cottages with individual heat sources using blue fuel. That is why developers and homeowners who are just choosing a gas boiler for themselves should calculate heating costs in advance.

Initial data for calculations

To perform a preliminary calculation, you need to find out the following parameters:

• the calorific value (calorific value) of natural gas supplied in your area;
• The efficiency of the boiler, which is planned to be installed in a house or apartment.

The calorific value of the fuel is taken according to the value of the lower calorific value of the main gas.

Theoretically, when burning 1 m³ of blue fuel, 9.2 kW of thermal energy is released. In practice, this value differs and, as a rule, to a smaller extent. Due to the same rise in price, some unscrupulous suppliers dilute the gas with air, which can reduce its calorific value to 7.5-8 kW / m³.

To determine the gas consumption for heating a house, it is better to find out the calorie value from the management company, and when this fails, take into account the figure with a margin: 8 kW / m³. If they share information with you about the specific heat of combustion and give a figure expressed in other units, kcal / h, then you can convert it to Watts by multiplying by a factor of 1.163.

Another important indicator that directly affects fuel consumption is the heat load on the heating system, which consists of heat losses through the building structures of the building and losses for heating the ventilation air. The best option is to perform or order an accurate calculation of all heat losses, but in the absence of another way out, you can determine the load in enlarged ways:

1. If the ceiling height does not exceed 3 m, then a heat consumption of 0.1 kW per 1 m² of the heated building area is assumed. Thus, for a house of 100 m2, about 10 kW of heat is needed, 150 m2 - 15 kW and 200 m2 - 20 kW of heat energy.
2. Put 40-45 W of heat per 1 m³ of heated space. The load is determined by multiplying this value by the volume of all heated rooms.

The efficiency of the heat generator, which affects the efficiency of fuel combustion, is indicated in its technical passport. If the unit has not yet been purchased, then you can take the efficiency of gas boilers of various types from the list:

• gas convectors - 86%;
• boilers with an open combustion chamber - 88%;
• heat generators with a closed chamber - 92%;
• condensing boilers - 96%.

Performing calculations

Preliminary calculation of gas consumption for heating is made according to the formula:

V \u003d Q / (q x efficiency / 100).

• q is the calorific value of the fuel, the default is 8 kW/m³;
• V is the desired flow rate of the main gas, m³ / h;
• Efficiency is the efficiency of fuel combustion by a heat source, expressed in %;
• Q is the heating load of a private house, kW.

As an example, it is proposed to calculate the gas consumption in a small cottage with an area of ​​150 m² with a heating load of 15 kW. It is planned that the task of heating will be performed by a heating unit with a closed combustion chamber (92% efficiency). The theoretical fuel consumption for 1 hour in the coldest period will be:

During the day, the heat generator will consume 2.04 x 24 = 48.96 m³ (rounded - 49 cubic meters) of natural gas - this is the maximum consumption on the coldest days. But during the heating season, the temperature can fluctuate between 30-40 ° C (depending on the region of residence), so the average daily gas consumption will be half as much, about 25 cubic meters.

Then, on average per month, a turbocharged boiler uses 25 x 30 = 750 m³ of fuel to heat a house with an area of ​​​​150 m², located in central Russia. In the same way, consumption is calculated for cottages of other sizes. Focusing on a preliminary calculation, it is possible to carry out measures aimed at reducing consumption even at the construction stage: insulation, selection of more efficient equipment and the use of automatic controls.

Autonomous heating of private houses with liquefied propane or its mixture with butane has not yet lost its relevance in the Russian Federation, although in recent years it has noticeably increased in price. It is all the more important to calculate the future consumption of this type of fuel for those homeowners who plan such heating. The same formula is used for the calculation, only instead of the net calorific value of natural gas, the value of the parameter for propane is set: 12.5 kW with 1 kg of fuel. The efficiency of heat generators when burning propane remains unchanged.

Below is an example calculation for the same building of 150 m², only heated with liquefied fuel. Its consumption will be:

• for 1 hour - 15 / (12.5 x 92 / 100) = 1.3 kg, per day - 31.2 kg;
• on average per day - 31.2 / 2 \u003d 15.6 kg;
• on average per month - 15.6 x 30 \u003d 468 kg.

When calculating the consumption of liquefied gas for heating a house, it must be taken into account that fuel is usually sold by volume measures: liters and cubic meters, and not by weight. This is how propane is measured when filling cylinders or a gas tank. This means that it is necessary to convert mass into volume, knowing that 1 liter of liquefied gas weighs about 0.53 kg. The result for this example will look like this:

468 / 0.53 \u003d 883 liters, or 0.88 m³, of propane will have to be burned on average per month for a building with an area of ​​​​150 m².

Given that the retail price of liquefied gas is an average of 16 rubles. for 1 liter, heating will result in a considerable amount, about 14 thousand rubles. per month for the same cottage for one and a half hundred squares. There is reason to think about how best to insulate the walls, and take other measures aimed at reducing gas consumption.

Many homeowners expect to use fuel not only for heating, but also for providing hot water. These are additional costs, they must be calculated, plus it is important to take into account the additional load on heating equipment.

The thermal power required for hot water supply is easy to calculate. It is necessary to determine the required amount of water per day and use the formula:

Q DHW \u003d cm (t 2 - t 1).

• c is the heat capacity of water, equal to 4.187 kJ/kg °C;
• t 1 - initial water temperature, ° С;
• t 2 - final temperature of heated water, ° С;
• m is the amount of water consumed, kg.

As a rule, economical heating occurs up to a temperature of 55 ° C, and this must be substituted into the formula. The initial temperature is different and lies in the range of 4-10 °C. For a day, a family of 4 people needs approximately 80-100 liters for all needs, subject to economical use. It is not necessary to convert the volume into mass measures, since in the case of water they are almost the same (1 kg \u003d 1 l). It remains to substitute the obtained value of Q DHW in the above formula and determine the additional gas consumption for DHW.